hash timings

<?phpfunction microtime_float() { list($usec, $sec) = explode(' ', microtime()); return ((float)$usec + (float)$sec);}function file_crc($file) { $file_string = file_get_contents($file); $crc = crc32($file_string); return sprintf("%u", $crc);}function sfv_checksum($file) { $sfv_checksum = dechex(crc32(file_get_contents($file))); return $sfv_checksum;}function read_dir() {$dir = '';$i = 0;if ($handle = opendir($dir)) { while (false !== ($file = readdir($handle))) {  if ($file != "." && $file != "..") {   $files[] = $dir.'/'.$file;   $i++;   if ($i >= 10000) return $files;  } } closedir($handle);} return $files;}$files = read_dir();foreach($files as $file) {$a = microtime_float();$crc = crc32(implode(file($file)));$b = microtime_float();$crc2 = file_crc($file);$c = microtime_float();$md5 = md5_file($file);$d = microtime_float();$sha1 = sha1_file($file);$e = microtime_float();$sfv = sfv_checksum($file);$f = microtime_float();$times[0][] = ($b-$a);$times[1][] = ($c-$b);$times[2][] = ($d-$c);$times[3][] = ($e-$d);$times[4][] = ($f-$e);}echo 'crc32 takes'."\t".array_sum($times[0])."\n";echo 'file_crc takes'."\t".array_sum($times[1])."\n";echo 'md5 takes'."\t".array_sum($times[2])."\n";echo 'sha1 takes'."\t".array_sum($times[3])."\n";echo 'sfv takes'."\t".array_sum($times[4])."\n";/*OUTPUTcrc32 takes     29.046131134033file_crc takes  7.7869794368744md5 takes       7.2286281585693sha1 takes      7.4805948734283sfv takes       7.0564570426941*/?>